Wireless charging of batteries of electronic devices has historically been performed by using inductive coupling. A charging base station receiver of an electronic device may have one or more coils in which a current may be applied to produce a magnetic field such that when another coil is placed in close proximity, a transformer effect is created and power is transferred between the coils. However, such inductive coupling has a limited short range, such as a few inches or less. Examples of such wireless charging include electronic toothbrushes that are placed on a charging stand and inductive pads inclusive of one or more coils to enable electronic devices with coil(s) to be placed on the pads to be charged.
While inductive charging is helpful to eliminate users having to plug power cords into electronic devices for charging, the limited range at which electronic devices have to be positioned from charging stations is a significant shortcoming of the inductive charging technology. For example, if a user of a mobile device, such as a mobile telephone, is in a conference room without a charging pad or sufficient number of charging pads, then the user is unable to charge his or her phone without a traditional power cord.
Remote wireless charging has recently been developed. Remote wireless charging operates by generating a wireless signal carrying sufficient power that can be directed to charge a battery of an electronic device or to operate the wireless device. Such technology, however, has been limited due to technology advancements being a challenge, as transmitters, receivers, antennas, communications protocols, and intelligence of transmitters have all had to be developed (i) so that sufficient wireless power is able to be wirelessly directed to charge electronic devices and (ii) so that the remote wireless charging is effective and safe for people.
Electronic devices are becoming smaller and as such, receivers and antennas for receiving wireless power to charge the electronic devices are also to become smaller. Such receivers and antennas are to be able to receive multi-polarized wireless power signals in order to be more efficient in receiving and charging wireless power signals. One problem that exists with smaller antennas is that their efficiency can become lower especially as an array of closely spaced antennas are used in receiving RF signals.